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Patent Number: 5,204,905  Date of Patent: Apr. 20, 1993
A text-to-speech synthesizer comprises an analyzer that decomposes a sequence of input characters into phoneme components and classifies them as a first group of phoneme components or a second group if they are to be synthesized by a speech parameter or by a formant rule, respectively. Speech parameters derived from natural human speech are stored in first memory locations corresponding to the phoneme components of the first group and the stored speech parameters are recalled from the first memory in response to each of the phoneme components of the first group. Formant rules capable of generating formant transition patterns are stored in second memory locations corresponding to the phoneme components of the second group, the formant rules being recalled from the second memory in response to each of the phoneme components of the second group. Formant transition patterns are derived from the formant rule recalled from the second memory, and formants of the derived transition patterns are converted into corresponding speech parameters. Spoken words are digitally synthesized from the speech parameters recalled from the first memory as well as from those supplied from the converted speech parameters.
6 Claims, 4 Drawing Sheets